There are times when inching forward can look like progress. The slender eight-clause protocol finally agreed at the climate change talks in Durban early on Sunday morning after two weeks and a final 60-hour head-banging haggle is probably one of those occasions, a moment when it is cheerier to think of how bad things might have been than to rate the success of the final outcome. What was nearly a complete failure to agree even to go on trying to agree became instead a plan about a plan.

There is an unvarying conflict of interest in the fight against climate change between developed and developing economies. The question is who pays for the past, and how to pay for the future without the heaviest burden falling on those most vulnerable to climate change – the least developed countries and small island states. The Kyoto treaty rightly weighted the scales against the developed world. Ever since, the developed world has been trying to get a new deal, reflecting the rapid growth of some emerging economies, which now account for more than half of carbon emissions. Overcoming bitter opposition, especially from India, whose headline growth figures disguise a poverty level still running above 40%, was Durban's big success. In return, the Kyoto terms have been extended: that means the emerging economies get up to nine more years of penalty-free polluting. But with the ground cleared for a future deal covering all emissions whatever their source (and that means China too), the US has been deprived of one of its main arguments against signing up.

There is little else to cheer from Durban. There is to be a "legal framework", and some argue that the case for investing in the low-carbon economy has been improved. But quite how legal is undefined. The green fund to support mitigation efforts in the least developed countries is still alive, but no plan for a sustainable income stream has been agreed. There is still no certainty on whether the extension of the Kyoto terms will last for four years or five. There is a route map for negotiations for new emission levels that are both effective and acceptable, to be enforced from 2020.

The race to keep the rise in global temperatures below 2C is still winnable if there is a big change in the pace, but a 3-4C rise looks the most likely outcome. And the longer it goes on, the harder it gets. Bold unilateral moves like the Australian carbon tax, due to take effect from July next year, now look like a trip to the moral high ground at the expense of international competitiveness. The case for urgent investment in renewable technology is undermined. The Durban deal is indeed better than nothing. But nothing would have been a catastrophe.